Biographical note

Roger Plymen is Emeritus Professor at Manchester University and Visiting Professor at Southampton University. He recently published 'The Great Prime Number Race' (2020). His paper from 1983, “The Dirac Operator and the Principal Series for Complex Semisimple Lie Groups,” co-authored by Michael G. Penington, was a springboard for several of the developments in this book. Mehmet Haluk Şengün is Senior Lecturer at University of Sheffield. Originally from Istanbul, Dr. Şengün's mathematical trajectory took him to Madison, Essen, Barcelona, Bonn, Warwick and finally Sheffield. An algebraic number theorist by training, Dr. Şengün's recent research has focused on bringing tools and ideas from C*-algebras and Noncommutative Geometry to the theory of automorphic forms and the Langlands Programme.